1. Field of the Invention
The present invention relates to an apparatus for conducting heating/cooling treatment for treating a plate-like material such as a semiconductor wafer, a glass substrate, a ceramic substrate or the like, and a heating/cooling treatment method thereof.
2. Description of Prior Art
Conventionally, for forming an integrated circuit on the surface of a plate-like material to be treated such a semiconductor wafer, a glass substrate or the like, the surface of the plate-like material to be treated is covered with a resist mask having a predetermined pattern and various kinds of treatments, such as a CVD method or an etching process, are conducted onto the resist mask. In particular, recently, because of the high integration and the high density of circuits, fine processing has been required more and more. Also, in order to meet such a demand, formation of a resist film or an insulating film having high accuracy has been required.
For fine processing, a resist film having high sensitivity is necessary. It has been acknowledged that quenching a resist film formed by heat treatment is effective for heightening the sensitivity.
In a case of forming an insulating film on the surface of a material to be treated, for forming an insulating film having lower permittivity, it is required that the oxidation of the film be prevented by cooling the film in advance of exposing it to air.
A conventional heat treatment apparatus is known, in which a cooling plate and a heating plate are provided and are arranged vertically one above the other within a chamber, for quenching a material to be treated just after heating or successively conducting heating and cooling in a non-oxidizing atmosphere. In this apparatus, a material to be treated is heated on the heating plate provided, for example, at the lower portion of the chamber, the material to be treated is lifted up by means of a lift pin to be adjacent to the cooling plate provided at the upper portion of the chamber, and a resist film or an insulating film formed on the surface of the material to be treated is quenched.
However, the conventional apparatus having a heating plate and a cooling plate provided in a chamber has a drawback that the heating plate or the cooling plate is deformed because the temperature gradient is extremely large within the chamber. Also, there is another drawback that a supporting member is deformed by the temperature variation and the material to be treated cannot be held reliably in a horizontal position. Accordingly, even if the material to be treated is set to be parallel with either of the heating plate or the cooling plate which is provided at the lower portion when the material is lifted up with the lift pin, heat treatment gradually deforms the heating plate or the cooling plate and affects the parallel arrangement.
Further, in the conventional apparatus, since it is not possible to accurately measure the distance between the heating plate or the cooling plate and the surface of the material to be treated under the treatment, it is very hard to control the temperature of the material to be treated.
Specifically, if a heating plate of 500xc2x0 C. is provided at the lower portion of a chamber, a cooling plate of 28xc2x0 C. is provided at the upper portion of the chamber, and the distance between the surface of a material to be treated and the cooling plate is set at 70 mm, dislocation of 1 mm in the distance causes a temperature difference of 45xc2x0 C. around the cooling plate in such a heat treatment apparatus.
According to the present invention, for the purpose of overcoming the drawbacks mentioned above, there is provided a heat treatment apparatus comprising a chamber, a cooling plate and a heating plate, plural lift pins, a supporting member for supporting the plural lift pins, and an elevator member to which the supporting member is attached through a joint so that the supporting member can move while inclining relative horizontal and can be fixed at any inclined angle, wherein a material to be treated is lifted up with the plural lift pins and thereby the surface of the material to be treated is allowed to approach the heating plate or the cooling plate very closely.
With such a structure, it is possible to automatically adjust the distance and the parallel condition between the heating plate or the cooling plate and the material to be treated.
In a case where the heating plate and the cooling plate are provided in a parallel orientation, arranged in vertical alignment and vertically separated from one another, the heat treatment apparatus mentioned above has a structure for allowing the lift pins to penetrate either of the heating plate or the cooling plate which is located in the lower portion.
Also, when a detecting mechanism such as an air micrometer for detecting the distance between the heating plate or the cooling plate located in the upper portion and the surface of the material to be treated is provided, for example, in the upper plate, the distance between the material to be treated under the treatment and the plate can be measured.
As the joint, a spherical bearing having a movable portion and a fixed portion can be used. By feeding gas to between the opposing surfaces of the movable portion and the fixed portion, it is possible to make the supporting member movable in an inclined condition. By aspirating the gas, it is possible to fix the supporting member. An electromagnetic force may be used instead of gas.
According to the present invention, there is also provided a heat treatment method using the heat treatment apparatus mentioned above, comprising the steps of bringing the supporting member into a condition where inclining movement is possible, elevating the plural lift pins without having a material to be treated mounted thereon, making the upper edge of all lift pins push onto the lower surface of the heating plate or the cooling plate which is provided in the upper portion of the chamber, fixing the movable portion of the bearing with respect to the fixed portion of the bearing, lowering the lift pins, mounting a material to be treated on the lift pins, elevating the lift pins again, allowing the surface of the material to be treated to approach the heating plate or the cooling plate which is provided in the upper portion of the chamber, and conducting heat treatment.